Transformers for providing a voltage output are known. For example, high speed transformers such as a Magnetic Linear Adder Transformer include a secondary, for example, a “stalk,” with one end attached to ground and the other end being the high voltage output terminal. A series of Toroidal primaries are stacked on the stalk. Each primary pulse adds to the energy (voltage) in the secondary.
A disadvantage of the Magnetic Linear Adder Transformer is that Toroidal-shaped primaries will go into saturation and collapse the field if they are driven with too large a pulse. This limits the amount of energy that one can extract from this type of transformer. A further disadvantage is a resulting pulse having a “staircase” leading edge, rather than a smooth leading edge.
Therefore, it would be desirable to provide a transformer for creating a high voltage pulse that avoids the foregoing problems of saturation and the leading edge of a pulse having a “staircase” pattern.
According, the invention provides an electron-coupled transformer for generating a high voltage output pulse as an amplified version of an input pulse. The electron-coupled transformer comprises a cylindrical coaxial triode electron tube with a central anode along the main axis of the tube and a cylindrical grid and a cylindrical cold cathode which are radially and coaxially spaced from the anode. The grid-cathode spacing is constant across the length of the grid. The grid is configured to have a constant and uniform electric field in the grid-cathode region. All edges of the grid have a radius equal to half the thickness of the associated material of the grid, and the grid lacks sharp edges or burs. The anode has an input end directly grounded and an output end insulated from a direct connection to ground. The cylindrical cold cathode is receptive of said input pulse via a cathode feedthrough and forms a primary of the transformer and the output end of the anode forms a secondary of the transformer. The cylindrical cold cathode and the cylindrical grid form a traveling wave electron gun with a circular waveguide structure; the traveling wave electron gun produces, when an input end of the grid is grounded through a phase matching network, a radially symmetrical collapsing traveling wave of ground potential in the Transverse Electromagnetic mode. The foregoing traveling wave of ground potential propagates along the length of the traveling wave electron gun in a direction from the input end of the anode to the output end of the anode. The foregoing traveling wave of ground potential causes a beam of electrons to flow from the cylindrical cold cathode to the anode and causes a voltage output pulse to be produced on the output end of the anode, whose magnitude is an amplified version of said input pulse that is injected into the cylindrical cold cathode. The cylindrical cold cathode and the grid are configured so that the distributed interelectrode capacitance formed by the cylindrical cold cathode and the grid stores energy. Such energy is supplied by the input pulse. At least such energy pumps the Electron-coupled transformer.
The foregoing electron-coupled transformer beneficially avoids the saturation and “staircase” leading pulse edge problems associated with Magnetic Linear Adder Transformers mentioned above.
Other advantages and features of the invention will become apparent from reading the detailed description in conjunction with the drawing figures.